Researchers debunk 'obesity paradox' for people with diabetes

Friday

Jan 17, 2014 at 12:01 AMJan 17, 2014 at 11:23 AM

For people with Type 2 diabetes who had hoped that their love handles might reduce their risk of premature death, Harvard researchers have bad news: The "obesity paradox" does not exist. "We found no evidence of lower mortality among patients with diabetes who were overweight or obese at diagnosis, as compared with their normal-weight counterparts, or of an obesity paradox," the research team reported in a study that appeared in yesterday's New England Journal of Medicine.

For people with Type 2 diabetes who had hoped that their love handles might reduce their risk of premature death, Harvard researchers have bad news: The “obesity paradox” does not exist.

“We found no evidence of lower mortality among patients with diabetes who were overweight or obese at diagnosis, as compared with their normal-weight counterparts, or of an obesity paradox,” the research team reported in a study that appeared in yesterday’s New England Journal of Medicine.

What the team from the Harvard School of Public Health, Harvard Medical School and Brigham and Women’s Hospital did find will dishearten those with a body mass index outside the 22.5-to-24.9 range, which is considered the higher end of “normal” weight.

Compared with people in this index group, people with a BMI between 30 and 34.99 (considered “ obese”) were 24 percent more likely to die during the course of the study, and people with a BMI above 35 (considered “severely obese”) were 33 percent more likely to die.

People whose BMIs were in the 25-to-29.99 range (“overweight”) also had higher rates of premature death, though the difference wasn’t large enough to be statistically significant.

The data also offer sobering news for diabetes patients on the lower end of the normal range. Compared with people in the index group, those with a BMI between 18.5 and 22.4 were 29 percent more likely to die of any cause during the study.

These findings are in line with some previous studies, but they contradict several other reports that identified a surprising relationship that came to be known as the obesity paradox.

In these studies, people who were obese were less likely to die than people with a “healthy” weight. Examples of the obesity paradox have been seen among people with diabetes, people with various kinds of heart disease and people on dialysis.

Why did these results contradict studies that found an obesity paradox? The researchers raised several possibilities.

One problem might be that the earlier studies followed volunteers for a shorter period of time and recorded fewer deaths, making the true signal harder to find.

Also, some studies did not take into account smoking or undiagnosed chronic diseases, which could skew the results.

The Harvard researchers concluded: “The maintenance of a healthy body weight should remain the cornerstone of diabetes management.”